A message box or e-mail that is filled with spam that is yet to be sent or submitted. Upon being sent or submitted, the spam is released into the chat box or message box for people to read.
Chatter 1: CHOWDA BAWM CHOWDA BAWM CHOWDA BAWM....
Chatter 2: "What is his problem?"
Chatter 3: "I bet he built up a Spam Dam to do this."